Dispersing fragrances

ABSTRACT

A fragrance disperser ( 10 ) in one form includes a single fan ( 101 ) that passes air over a wicked single or double fragrance ( 102 ). A second form has the fan ( 11 ) reversible to provide two different airstreams ( 29   a   , 29   b   ; 60   a   , 60   b ) that evaporate respective different fragrances one after the other. Where two fragrances are provided, the evaporation may be by respective electrical heaters. A fragrance source may be formed by two sheets ( 31, 40; 47, 48 ) joined together to form two chambers each receiving a respective wick ( 37   a   , 37   b   ; 56   a   , 56   b ) and having respective exposed wick portions. The source may incorporate a source of electrical power ( 45 ). An alternative source ( 81   a   , 81   b ) has a reservoir ( 82   a   , 82   b ) for fragrance and a wick ( 87   a   , 87   b ) located in an air passage ( 83   a   , 83   b ) forming part of the source so that an air flow is guided through the passage past the wick to evaporate fragrance. Where two fragrances are provided, the fragrance sources may be located side-by-side and matching fragrances may have, for example, matching indicia ( 95, 96 ) on the sources so that the match can be easily determined visually.

The invention relates to fragrance dispersers, fragrance sources and fragrance containers.

Fragrance dispersers are used to release one or more fragrances into an enclosed space such as a room. In general, the fragrance is held by a fragrance source and released either by natural convection or by forced convection or by heating a wick or pad, for example, holding the fragrance.

According to a first aspect of the invention, there is provided a fragrance disperser comprising a source of fragrance and means for generating a flow of air to release said fragrance.

One form of fragrance source is a container containing a liquid fragrance. The fragrance is released by a convection air current passing across an outlet for the fragrance. It is a problem that this does not provide a directed flow of air.

According to a second aspect of the invention, there is provided a fragrance container comprising a reservoir for receiving a liquid fragrance and an outlet to the reservoir, the outlet defining a path for a flow of air to release fragrance in the reservoir.

Many fragrance sources are complicated to manufacture including separate containers and wicks.

According to a third aspect of the invention, there is provided a fragrance source comprising a back sheet and a front sheet with a wicking material therebetween the back sheet and the front sheet being joined together along a closed line to define a reservoir for fragrance, a portion of the wicking material being exposable outside the closed line for releasing the fragrance, the join being such as to allow the wicking material to wick fragrance from the reservoir to the exposable portion.

According to a fourth aspect of the invention, there is provided a fragrance disperser comprising two sources of fragrance, means for dispersing fragrance from said sources and a control system for controlling said dispersing means.

The following is a more detailed description of some embodiments of the invention, by way of example, reference being made to the accompanying drawings in which:

FIG. 1 is a schematic front elevation of a first form of fragrance disperser, a front cover of the disperser being removed to show a fan of the disperser and a fragrance source, the fan rotating in a first sense,

FIG. 2 is a similar view to FIG. 1 but showing the fan rotating in an opposite sense,

FIG. 3 is a cut-away side elevation of the fragrance disperser of FIGS. 1 and 2,

FIG. 4 is a section on the line A-A of FIG. 3,

FIG. 5 is a perspective view of the fragrance source of FIGS. 1 to 4,

FIG. 6 is an exploded view of the fragrance source of FIG. 5,

FIG. 7 is a graph of time against operational state for the fragrance disperser of FIGS. 1 to 4,

FIG. 8 is a perspective view of a second form of fragrance source for use with the fragrance disperser of FIGS. 1 and 2, two wicks of the source being shown separated from the source for clarity,

FIG. 9 is an exploded view of the second form of fragrance source of FIG. 8,

FIG. 10 is a front elevation of a second form of fragrance disperser, and two fragrance sources,

FIG. 11 is a front elevation of the second form of fragrance disperser of FIG. 10 with a front cover removed and showing a fan rotating in one sense,

FIG. 12 is a similar view to FIG. 11 but showing the fan rotating in an opposite sense,

FIG. 13 is an internal view from above of the second form of fragrance disperser,

FIG. 14 is a cross-section on the line B-B of FIG. 12,

FIG. 15 is a similar view to FIG. 10 showing the second fragrance disperser provided with buttons that allow different modes of operation,

FIG. 16 is a similar view to FIG. 10 showing the second fragrance disperser with shutters that control the volume of fragrance dispersed,

FIG. 17 corresponds to FIG. 16 but shows one of the shutters in a fully open position and the other in a partially closed position,

FIG. 18 is a similar view to FIG. 11 showing the second fragrance dispenser with wick cover assemblies that control the volume of fragrance dispersed,

FIG. 19 corresponds to FIG. 18 but shows one of the wick covers covering a wick to a minimum degree and the other covering another wick to a maximum degree,

FIG. 20 is a similar view to FIG. 14 but with the fragrance source including a peg and the fragrance disperser including a microswitch operable by the peg,

FIG. 21 is a side view of a fragrance source of FIGS. 9 to 13 and including a peg but with the fragrance and wick removed,

FIG. 22 is a schematic view of the fan of the second form of fragrance disperser together with a shutter,

FIG. 23 is a schematic cross-section of the fan and shutter of FIG. 22 showing the parts interconnected by a frictional clutch,

FIG. 24 is a schematic cross-section of the fan and shutter of FIG. 22 showing the parts interconnected by a centrifugal clutch,

FIG. 25 is a plan view of a first clutch part of the centrifugal clutch of FIG. 24,

FIG. 26 is a plan view of a second clutch part of the centrifugal clutch of FIG. 24,

FIG. 27 is a front elevation of a third form of fragrance disperser and two fragrance sources,

FIG. 28 is a front elevation of the third form of fragrance disperser with a front cover removed and showing a fan rotating in one sense,

FIG. 29 is a similar view to FIG. 24 but showing the fan rotating in an opposite sense,

FIG. 30 is a cut away side elevation of the fragrance disperser of FIGS. 28 and 29,

FIG. 31 is a cross-section on the line C-C of FIG. 29,

FIG. 32 is a side elevation of a fragrance source for use with the third forms of fragrance disperser, a cap of the source being removed,

FIG. 33 is a similar view to FIG. 32 but showing the internal structure of an outlet to the source,

FIG. 34 is a similar view to FIG. 32 but showing a flow of air through the outlet to the fragrance source,

FIG. 35 is a side elevation of a fragrance source of the kind shown in FIGS. 32 to 34 adjacent a second such source shown with the cap and outlet omitted,

FIG. 36 is a side elevation of a modified form of the fragrance source of FIGS. 32 to 34 adjacent a second such source with the cap and outlet omitted,

FIG. 37 is a schematic side elevation of a fourth form of fragrance disperser including a fan and a source of a single fragrance,

FIG. 38 is a similar view to FIG. 37 but with the source having two fragrances,

FIG. 39 is a schematic view of a fifth form of fragrance disperser including two sources of fragrance dispersed by heat and a control system,

FIG. 40 is a similar view to FIG. 39 but showing an alternative method of dispersing the fragrances by heat,

FIG. 41 is a schematic view of a fragrance disperser of any of the kinds shown in FIGS. 1 to 4 or FIGS. 10 to 19 or FIGS. 27 to 31 and mounted on a vertical surface.

Referring first to FIGS. 1 to 4, the fragrance disperser is formed by a housing 10, a fan 11 and a fragrance source 12.

The housing 10, which may be formed of any suitable material such as metal or plastics, is formed by a back wall 13, a side wall 14 and a front cover 15 (seen in FIG. 3). The back wall 13 is generally rectangular with parallel side edges 16 interconnected at one end by a straight lower end edge 17 and at the other end by a generally semi-circular end edge 18. The side wall 14 extends around the side edges 16 and the semi-circular upper end edge 18. The portion of the side wall 14 extending around the upper end edge 18 has an interior surface 19 (see FIGS. 1 and 2) formed by two-part spirals that meet at the apex of the end edge 18 and increase in radius from that point. This portion of the housing contains the fan 11 which is connected to a motor 21 by a drive shaft 22 (see FIG. 3). The motor 21 is connected to, and controlled by, a control board 23 mounted on the back wall 13.

The fragrance source 12 is also carried by the back wall 13 below the fan 11. The construction of this fragrance source 12 will be described in more detail below.

The front of the housing 10 is closed by the front cover 15 seen in FIGS. 3 and 4. The cover 15 has generally the same shape as the back wall 13 but is provided with an air inlet 26 aligned with the fan 11. In addition, as seen in FIG. 3, the cover is provided with an inwardly slanted wall 27 and a central divider 28. With particular reference to FIGS. 3 and 4, the wall 27 and the divider 28 form a pair of side-by-side ducts 29 a,29 b that converge as they extend away from the fan 11 and terminate in respective outlets one of which is shown at 30 in FIG. 3. The position of the divider 28 in relation to the fragrance source 12 will be discussed below.

The fragrance source 12 is shown in more detail in FIGS. 5 and 6. Referring to those Figures, the fragrance source 12 comprises a back sheet 31 which is of generally rectangular shape and may be formed, for example, from a plastics laminate. The back sheet 31 is provided with a lateral fold line 32 which divides the back sheet 31 into a main portion 33 and a flap 34. The end of the flap 34 is provided with a tab 35 and the surface of the flap on the inner side of the fold line 32 is provided with two adhesive frames 36 whose function will be described below.

First and second strips 37 a,37 b of wick material are placed on the inner surface of the main portion 33 of the back sheet 31. Each strip of wick material 37 a,37 b is of elongate rectangular shape provided towards one end with a pair of inwardly directed registering notches 39 a,39 b whose function will be described below. As seen in FIG. 6, the first and second strips 37 a,37 b are arranged side-by-side and parallel to one another.

The first and second strips 37 a,37 b are covered by a front sheet 40 that may also be of a plastics laminate and is the same size as the main portion 33 of the back sheet 31. The front sheet 40 is formed towards one edge with two windows 41 a,41 b. Each window is in register with a respective shorter portion of an associated one of the first and second strips 37 a,37 b between the notches 39 a,39 b and the adjacent end of the associated strip 37 a,37 b. Of course, the front sheet 40 may be formed in one-piece with the back sheet 31, extending from the edge of the back sheet 31 opposite the fold line 32.

The front sheet 40, when not formed in one-piece with the back sheet, is then connected to the back sheet along lines 42,43,44 by, for example, welding or gluing. The first connection line 42 is a rectangular line extending around the peripheries of the main portion 33 and the front sheet 40 and thus forms a closed chamber between these parts 33,40. The second connection line 43 is a longitudinal line which extends along the gap between the first and second strips 37 a,37 b thus sub-dividing the main chamber to form separate chambers each containing a respective strip 37 a,37 b. The third connection line 44 is a lateral line extending between the side edges of the main portion 33 and the front sheet 40 with the line 44 extending into the notches 39 a,39 b and being interrupted between the notches 39 a,39 b. Thus, each sub-chamber containing an associated strip 37 a,37 b is divided into a larger portion and a smaller portion separated by a neck with the smaller portion underlying an associated window 41 a,41 b.

Each larger portion of each sub-chamber is filled with a respective different liquid fragrance. The flap 34 is folded over the windows 41 a,41 b with the adhesive frames 36 sealing around the peripheries of the windows 41 a,41 b to close the windows 41 a,41 b. Finally, an under surface of the back sheet 31 is mounted on a source of electric power 45. This may be a flat dry cell battery.

In use, the fragrance source 12 is opened by pulling the tab 35 to open the peelable seal formed by the adhesive frames 36. The fragrance source 12 is then mounted in the housing 10 as briefly described above. In this position, the windows 41 a,41 b are, as seen in FIGS. 1 and 2, adjacent the outlets 30 with the divider 28 extending along the longitudinal connecting line 43 so that each window 41 a,41 b is in a respective duct 29 a,29 b. Each fragrance wicks to the associated window 41 a,41 b at a rate controlled both by the characteristics of the strips 37 a,37 b and the gaps between the notches 39 a,39 b. The source of electric power 45 includes contacts which connect the source of electric power 45 to the control system 23 for the motor 21 of the fan 11.

The motor 21 operates when connected to the source of electric power 45 and the fan 11 rotates in, for example, the clockwise direction shown in FIG. 1. This produces an air flow through the duct 29 a associated with the first window 41 a and so conveys the associated fragrance to the surrounding atmosphere. The convergence of the duct 29 a towards the associated outlet 30 increases the speed of the air as it passes across the window 41 a.

After a period of time, the control system 23 reverses the direction of rotation of the fan 11 so that it rotates in an anti-clockwise direction as shown in FIG. 2. The effect of this is to pass air along the duct 29 b and across the window 41 b so releasing the associated fragrance through the outlet 30 into the surrounding atmosphere.

Referring next to FIG. 7, this shows one mode of operation of the fan 11 under the control of the control system 23. T1 is the time for which the fan 11 rotates in, for example, the clockwise direction. This time is designed to allow the concentration of the first fragrance to reach a maximum. The dwell period T2 is designed to allow the first fragrance to disperse before the second fragrance is emitted. T3 is the time for which the fan rotates in, for example, an anti-clockwise direction to emit the second fragrance and allow it to reach a maximum and T4 is the dwell period that allows the second fragrance to disperse. The time for which each wick is inactive allows the fragrance to wick to the associated window for immediate evaporation when the wick becomes active. As will be seen, these intervals need not be equal. They may be varied depending on the fragrance. There is a known phenomenon called olfactory fatigue where, after a time a person smelling a fragrance at a stable concentration becomes unaware of the smell. This time varies from fragrance to fragrance and the intervals mentioned above may be adjusted in accordance with those times. In addition, the time intervals may be able to be manually adjusted by the user. Further, the control system could be programmed to accommodate small or large rooms or to provide a booster fragrance on demand.

The timing may be altered for different sized rooms in a number of different ways. For example, for a larger sized room, it may be desirable to increase the on times T1, T3 for fragrances 1 and 2 whilst leaving the off times T2, T4 (the dwell periods) unchanged. Alternatively, the cycle could be altered by leaving the on times T1, T3 unchanged but shortening the dwell periods T2, T4. Another possibility is to increase both the on and off times whilst keeping the on/off ratio unchanged. Similarly for smaller rooms it may be desirable to reduce the on times T1, T3 only, or to increase the dwell periods T2, T4 only, or to shorten both whilst maintaining the same ratio. When the fragrance source 12 is finished, it can be replaced by a new fragrance source 12 on an associated source of electric power 45. The power of the source 45 is matched to the volume of fragrance so that when the power of the source is running low the amount of fragrance remaining is also running low. The control system 23 may monitor battery power and provide an indication when the power is running low so providing an indication that the fragrance is close to exhaustion and requires replacement. The indication may be a visual indication provided, for example, by an LED on the housing 10.

A second form of fragrance source for use with the fragrance disperser of FIGS. 1 and 2 is shown in FIGS. 8 and 9. The second fragrance source 46 is formed by a rectangular back sheet 47 which may be of a plastics laminate and a similar shaped front sheet 48 of the same material. Two valve inserts 49 a,49 b are also provided. Each valve insert 49 a,49 b is formed by a short section of tube 50 a,50 b and a pair of diametrically opposed outwardly extending wings 51 a,51 b. Each tube 50 a,50 b contains a pierceable seal (not shown).

The back sheet 47 is placed beneath the front sheet 48 with the valve inserts 49 a,49 b spaced apart along registering edges of the sheets 47,48. The sheets 47,48 are then connected together along lines 53,54 by, for example, welding or gluing. The first line 53 extends around the peripheries of the back sheet 47 and the front sheet 48 and also connects to the wings 51 a,51 b and the tubes 50 a,50 b of the valve inserts 49 a,49 b. The second line 54 is a longitudinal line extending between the edge of the sheets 47,48 including the valve inserts 49 a,49 b and the opposite edge. The back sheet 47 and the front sheet 48 thus form between them a chamber which is sub-divided by the longitudinal line into two sub-chambers. Each chamber contains an associated different liquid fragrance.

The second fragrance source 46 also includes two inserts 55 a,55 b. Each insert 55 a,55 b is formed by a generally rectangular area of wick material and an elongate capillary connector 57 a,57 b projecting from the associated wick material 56 a,56 b.

In use, the seals 52 in the valve inserts 49 a,49 b retain the associated fragrance in the sub-chambers. When it is wished to use the second fragrance source, each capillary connector 57 a,57 b is inserted through an associated seal of a valve insert 49 a,49 b to reach the fragrances in the sub-chambers. The fragrances pass along the capillary connectors 57 a,57 b to the associated wick materials 56 a,56 b where they evaporate.

The second fragrance source 46 may be mounted and used with the fragrance disperser as described above with reference to FIGS. 1 to 4.

Referring next to FIGS. 10 to 14, the second form of fragrance disperser has parts common to the fragrance disperser of FIGS. 1 to 4. Those parts will be given the same reference numerals as the corresponding parts in FIGS. 1 to 4 and will not be described in detail.

In the second fragrance disperser, the fragrance is supplied by two containers 58 a,58 b. Each container 58 a,58 b is connected to the housing 10 in a manner to be described below and includes a projecting wick 59 a,59 b received in an associated shaped duct 60 a,60 b formed in the housing 10.

Each container 58 a,58 b is formed with a neck 61 a,61 b surrounding a mouth 62 a,62 b. Each neck has an outwardly directing flange 63 a,63 b and the associated wick 59 a,59 b extends out of each mouth 62 a,62 b. The housing is formed at the lower end edge 17 with two apertures 64 a,64 b each for receiving the neck 61 of the associated container 58 a,58 b. As seen particularly in FIG. 14, each aperture 64 a,64 b includes a retention mechanism for holding the associated container 58 a,58 b connected to the housing 10.

The retention mechanism is formed by an inwardly directed projection 65 that extends under the flange 63 a,63 b of the associated container 58 a,58 b and a peg 66 that retracts against a spring 67 as the neck 61 a,61 b is pushed into the associated aperture 64 a,64 b to allow the flange 63 a,63 b to pass the peg 66 and then is forced outwardly by the spring 67 to engage behind the flange 63 a,63 b to hold the associated container 58 a,58 b in position.

Each shaped duct 60 a,60 b extends from a respective side of the fan 11 initially in a direction tangential to the fan 11. Then, as seen in FIG. 14 the duct 60 a,60 b turns through 90° to terminate in an outlet 68 a,68 b on the cover 15. As seen in FIGS. 11, 12 and 14, each wick 59 a,59 b extends along the associated duct 60 a,60 b to terminate adjacent the periphery of the fan 11. The fan 11 is associated with a shutter 69 which is carried on the drive shaft 22 and includes an arcuate wall 70. As seen in FIG. 11, when the fan 11 rotates in a clockwise direction, the wall 70 of the shutter 69 closes the duct 60 b and leaves the duct 60 a open so minimizing the volume of air leaving the duct 60 b. When the fan 11 rotates in an anti-clockwise direction, the wall 70 of the shutter 69 closes the other duct 60 a leaving the duct 60 b open and so minimizing the volume of air leaving the duct 60 a.

The construction and operation of the shutter 69 will be described in more detail below.

In use, the second fragrance disperser described above with reference to FIGS. 10 to 14, operates broadly as described above with reference to FIGS. 1 to 4. Air from the fan passes along one or other of the shaped ducts 60 a,60 b and evaporates fragrance from the associated wick 59 a,59 b which then passes out of the associated outlet 68 a,68 b into the surrounding atmosphere. The shape of the duct 60 a,60 b ensures that air from the fan 11 does not pass simply axially along the wicks 59 a,59 b. Rather, the shape of the ducts 60 a,60 b results in a circumferential flow of air around the wicks 59 a,59 b. This results in more efficient evaporation of fragrance from the wicks 59 a,59 b.

Power for the motor 21 is provided from an external power supply such as a battery (not shown) or a source of mains power.

When a container 58 a,58 b is empty, it can be released from the retention mechanism and replaced by a fresh container.

Referring now to FIG. 15, parts common to FIG. 15 on the one hand and FIGS. 10 to 14 on the other hand will be given the same reference numerals and will not be described in detail. In this arrangement the housing 10 is provided with three control buttons 111,112,113. On pressing the button 111, the timing protocol is altered to be suitable for smaller rooms. Pressing the button 112 alters the timing protocol to be suitable for larger rooms. Pressing the button 113 alters the timing protocol for a set limited period of time. For that limited period of time, the volume of fragrance emitted is increased. This provides a boost of fragrance. Alternatively, instead of changing the time periods for which the fan 11 operates, the speed of the fan 11 could be increased or decreased to alter the volume of fragrance emitted. This could be achieved by the varying power supplied to the motor.

Other means for controlling the volume of fragrance emitted will now be described with reference to FIGS. 16 to 19, in which parts common to FIGS. 10 to 15 on the one hand and to FIGS. 16 to 19 on the other hand will be given the same reference numerals and will not be described in detail.

Referring first to FIGS. 16 and 17, the size of each duct opening 68 a,68 b is controlled by a respective shutter assembly 210 a,210 b. Each assembly 210 a,210 b comprises a shutter 211 a,211 b to which is connected a peg 212 a,212 b which is slidably movable in a vertical slot 213 a,213 b in the front cover 15 of the disperser, such that when the peg 212 a 212 b is at the top of the slot 213 a,213 b the shutter is in a fully open position and the duct opening 68 a,68 b is a maximum size, and when the peg is at the bottom of the slot the shutter is in a fully closed position and the duct opening is a minimum size. This may correspond to completely closing off the duct opening 68 a,68 b.

Each shutter assembly 210 a,210 b may be controlled independently to control the relative volumes of each fragrance emitted. In FIG. 16, both shutters 211 a,211 b are shown in the fully open position, and the respective pegs 212 a 212 b can be seen at the top of each respective associated slot 213 a,213 b. In FIG. 17, the right-hand shutter assembly 210 a is shown in an intermediate position, the shutter 21 la partially restricting the associated duct opening 68 a to reduce the volume of fragrance emitted from the associated container 58 a. In the same Figure, the left-hand shutter assembly 210 b is in the fully open position. Thus, for a given fan speed, or a given time for which the fan 11 is operational, a greater proportion of fragrance will be emitted from container 58 b than from container 58 a.

As described above, each shutter assembly is adjusted manually by means of the respective peg 212 a 212 b. Alternatively, the shutters 211 a,211 b may be controlled electronically, in which case the pegs 212 a 212 b and the slots 213 a,213 b may be disposed of.

Referring now to FIGS. 18 and 19, the exposed surface area of each wick 59 a,59 b is controlled by a respective wick cover assembly 220 a,220 b. Each wick cover assembly 220 a,220 b comprises a cap 221 a,221 b, a cover 222 a 222 b and a slider 223 a,223 b. The cap 221 a, 221 b is substantially cylindrical and is mounted on the upper surface of the associated wick 59 a,59 b and includes at its lower end an annular shoulder 224. The cover 222 a 222 b is substantially cylindrical and includes at each of its upper and lower ends an inwardly projecting annular lip 225 and 226 respectively. The slider 223 a,223 b is also substantially cylindrical and includes at its upper end an annular shoulder 227 and near its lower end and a horizontally projecting peg 228 a,228 b. The peg 228 a,228 b is slidably movable in a vertical slot (not shown) in the side wall 14 of the disperser. The slider 223 a,223 b is slidably mounted on the associated wick 59 a,59 b and is connected to the cover 222 a 222 b in the region of the annular shoulder 227 of the slider and the lower annular lip 226 of the cover. In this way, the cover 222 a 222 b is slid over the cap 221 a, 221 b by virtue of a corresponding sliding movement of the slider 223 a,223 b over the wick 59 a,59 b, which is, in turn, controlled manually by sliding the associated peg 228 a,228 b within its associated slot. The cover 222 a 222 b and the slider 223 a,223 b could alternatively be combined as a single part.

In a first position, corresponding to that shown for both wick cover assemblies 220 a,220 b in FIG. 18 and for the right-hand wick cover assembly 220 a in FIG. 19, the slider 223 a,223 b is in an upper position in which the annular shoulder 227 of the slider 223 a,223 b abuts the annular shoulder 224 of the cap 221 a, 221 b. In this position, the cover 222 a 222 b substantially entirely overlaps the cap 221 a,221 b, and the associated wick 59 a,59 b is thus exposed to a maximum extent.

In a second position, corresponding to that shown for the left-hand wick cover assembly 220 b in FIG. 19, the slider 223 b is in a lower position in which the upper lip 225 of the cover 222 b abuts the annular shoulder 224 of the cap 221 b. In this position, the cover 222 b extends beyond the cap 221 b and covers a portion of the wick 59 b. In this second position, the wick is thus exposed to a minimum extent, and for a given fan speed or a given time for which the fan 11 is operational, a lesser proportion of fragrance will be emitted than when the wick cover assembly 220 a,220 b is in the first position, by virtue of the reduced exposed wick surface area. The sliders 223 a,223 b may be positioned intermediate the first and second positions, and each is independently controllable to control the relative volumes of fragrance emitted from each respective container 58 a,58 b.

As with the shutter assemblies 210 a,210 b of FIGS. 16 and 17, control of the wick cover assemblies 220 a,220 b need not be manual. Indeed, it may be automatic, or electronic, in either case there being no need for the provision of the pegs 228 a,228 b and their associated slots in the side wall 14.

Referring next to FIGS. 20 and 21, the disperser of FIGS. 10 to 14 may be modified so that the operation of the disperser is varied in accordance with information derived from the associated containers 58 a

,58 b. Parts common to FIGS. 20 and 21 on the one hand and to FIGS. 10 to 14 on the other hand are given the same reference numerals and are not described in detail. In this arrangement, the flange 63 a,63 b

on the neck 61 a,61 b of each container 58 a,58 b is provided with a peg 109. When the container 58 a,58 b is engaged with the housing 10, the peg 109 engages an associated microswitch 110. The microswitch 110 passes a signal to the control system 23 that modifies the operation of the control system 23. For example, when a signal is received from the microswitch, the relevant cycle times may be altered in comparison with the cycle times when the peg 109 is absent.

Other arrangements are possible. For example, the container may include a readable microchip or bar code that provides information to the control system 23 for adjusting the operation of the fan 11.

Referring next additionally to FIGS. 22 to 25, these Figures illustrate various modes of operation of the shutter 69. As seen in FIG. 23, the shutter 69 comprises a generally frusto-conical portion 71 with the narrower end closed by an end wall 72. The drive shaft 22 passes through this end wall and is coaxial with the axis of the frusto-conical portion 71. A peripheral flange 73 extends outwardly of and around the wider end of the frusto-conical portion 71 and the wall 70 extends around a portion of this flange 73. In order to counter balance the wall 70, the diametrically opposite portion of the flange 73 may be thickened so that the shutter 69 is in static balance around the drive shaft 22.

In its simplest form of operation, the shutter 69 may be rotated only by the air flow generated by the fan 11. When the fan 11 is rotating in an anti-clockwise direction, there will be a corresponding anti-clockwise flow of air and, due to the balance of the shutter 69, this may be sufficient to rotate the shutter to the position shown in FIG. 11. Likewise, when the fan 11 rotates in a clockwise direction, there is a corresponding clockwise rotation of air which moves the shutter 69 to the position shown in FIG. 12.

There may, however, be cases where this movement cannot be achieved reliably by the use of air alone. In this case, and referring to FIG. 23, in an alternative arrangement, a felt washer 74 and a crimped washer 75 are provided on the drive shaft 22 between the end wall 72 of the shutter 69 and a mounting boss 76 of the fan 11 which is connected to drive shaft 22. In this arrangement, when the motor 21 rotates in one direction, the rotational movement of the fan 11 is transmitted frictionally by the washer 74, 75 to the shutter 69 so rotating the shutter 69 in the same sense as the fan. The arrangement works in whichever direction the motor 21 is rotated.

Another possibility is shown in FIGS. 24, 25 and 26. In this arrangement, the fan 11 carries a first clutch part 77 shown in FIG. 25. This clutch part 77 includes three arcuate arms 78 which, as the fan 11 rotates, move from the fall line position shown in FIG. 25 outwardly to the dotted line position shown in that Figure. The shutter 69 includes a second clutch part 79 (see FIG. 26) which includes three outwardly directed equi-angularly spaced projections 80. When the arms 78 are in the full line position shown in FIG. 25, they engage these projections 80 so locking the first and second clutch parts 77,79 together and thus rotating the shutter 69 with the fan 11. As the speed of the fan 11 increases, the arms 78 move to the dotted line position shown in FIG. 25 where they are disengaged from the projections 80 so allowing the fan 11 to rotate independently of the shutter 69 with the shutter 69 being maintained in position by air flow (and possibly friction).

It will be appreciated that these are only some of the ways in which the shutter 69 can be moved. Other ways are possible.

Referring next to FIGS. 27 to 31, the third fragrance disperser has parts common with the second fragrance disperser of FIGS. 10 to 14. Those common parts will be given the same reference numerals and their construction and operation will not be described in detail.

The third fragrance disperser includes two fragrance sources 81 a,81 b in which the wick is surrounded by an outlet formed by part of the source.

Referring particularly to FIGS. 28 and 29, each fragrance source 81 a,81 b includes a container 82 a,82 b holding a liquid fragrance and including an integral outlet 83 a,83 b. Each outlet 83 a,83 b is formed at its end remote from the container 82 a,82 b with an entrance 84 a,84 b and, at a point in the outlet 83 a,83 b adjacent the associated container 82 a,82 b, each outlet 83 a,83 b is formed with an exit 85 a,85 b (see FIG. 30). As seen in FIGS. 27 and 30, these exits 85 a,85 b are aligned with respective apertures 86 a,86 b in the cover 15 of the housing 10. Each outlet 83 a,83 b contains an upper portion of an elongate strip shaped wick 87 a,87 b whose lower end is immersed in the fragrance in the container 82 a,82 b. Each outlet is a snap fit in an associated shaped duct 60 a,60 b of the housing 10.

In use, rotation of the fan 11 in a clockwise direction produces an air flow which is forced through the first duct 60 a and enters the entrance 84 a of the outlet 83 a of the associated fragrance source 81 a. The air then passes over and around the wick 87 a releasing fragrance which then passes through the exit 85 a and through the aperture 86 a of the cover 15 to the surrounding atmosphere. Anti-clockwise rotation of the fan 11 produces, as seen in FIG. 25, a flow of air through the entrance 84 b of the outlet 83 b, past the associated wick 87 b and then through the exit 85 b and the cover aperture 86 b.

The cover apertures 86 a,86 b may be provided with respective shutter assemblies as described above with reference to FIGS. 16 and 17.

When a fragrance source 81 a,81 b is empty, it can be replaced by a fresh fragrance source.

In this embodiment, the wick 87 a,87 b is packaged within and protected by the outlet 83 a,83 b. The air duct is part of the fragrance source 81 a,81 b and is thus a consumable. Each wick 87 a,87 b may be provided with a wick cover assembly similar to those described above with reference to FIGS. 18 and 19, but adapted for consumable fragrance sources.

Referring next to FIGS. 32, 33 and 34, there is shown a fragrance source of a kind for use with the third form of fragrance disperser described above with reference to FIGS. 27 to 31. The fragrance source is formed by a container 88 comprising a reservoir 89 and an outlet 90. The parts may be formed from any suitable material such as a plastics material or glass. As seen in FIG. 34, the outlet 90 is formed at its end remote from the reservoir 89 with an entrance 91 and, at a point in the outlet 90 adjacent the reservoir 89, the outlet 90 is formed with an exit 92. A wick 93 leads from the reservoir 89 and terminates in the outlet 90 adjacent the entrance 91.

The reservoir 89 contains a fragrance. A shaped cap 94 covers the outlet 90.

This container 88 can be used with the fragrance disperser of FIGS. 27 to 31. The cap 94 is removed and the outlet 90 inserted into the housing 10. Air is then passed through the outlet 90 via the entrance 91 as described above. The air then leaves via the exit 92.

It will be seen from FIGS. 27 to 31, that, when mounted on the housing 10, the fragrance sources 81 a,81 b are side-by-side. It will be appreciated that these two fragrance sources 81 a,81 b, may contain different fragrances. Not all pairs of fragrances are perceived by the nose as being complementary and it is plainly desirable to avoid combinations that are perceived as non-complementary.

Proposals for overcoming this are shown in FIGS. 35 and 36.

Referring first to FIG. 35, two containers 88 a,88 b are provided of the kind described above with reference to FIGS. 32 to 34. A first container 88 a is provided with a surface pattern 95 that forms a continuous pattern with a corresponding pattern 96 on the second container 88 b, with the pattern being continuous across the junction between adjacent side surfaces 97 a,97 b of the containers 88 a,88 b. These containers 8 a,88 b are arranged to contain complementary fragrances (i.e. fragrances that are complementary in an olfactory sense) and any container containing a non-complementary fragrance has a different pattern which does not match the pattern of either of the containers in FIG. 30. Thus, if a container including a non-complementary fragrance is used with one of the containers illustrated in FIG. 30, the lack of matching pattern will be readily apparent. It will be appreciated that this effect need not be provided by a raised pattern. Inset patterns may be used or simply print effects.

Another possibility is provided by the arrangement of FIG. 36. In this Figure, one side surface 97 a of one container 88 a has a non-planar shape which is complementary with a non-planar shape of the side surface 97 b of the other container 88 b containing a complementary fragrance so that the side surfaces 97 a,97 b interlock when the containers 88 a,88 b are placed side-by-side in the housing 10. Containers holding non-complementary fragrances are provided with different side surface configurations and so will not be able to interlock and will thus not be able to be used.

The use of a fan to disperse fragrance need not be confined to the dispersal of two fragrances. Referring next to FIG. 37, a fourth form of fragrance disperser is formed by a housing 98 including a chamber having an inner wall 99 formed as a spiral of increasing radius and leading to an outlet 100 extending tangentially from the wall 99. A fan 101 is mounted in the housing 98 and is driven by a motor (not shown). The outlet contains a fragrance source 102 which may be formed by a half of the fragrance source described above with reference to FIGS. 5 and 6. The window 41 a lies within the outlet 100 and rotation of the fan passes air across the window 41 a to evaporate the fragrance.

In this embodiment, the fan 101 rotates in one direction only and so can be designed to be of high efficiency. The motor is controlled by a manually operated switch to give fragrance on demand. The motor is powered by a source of electric power of the kind described above with reference to FIGS. 5 and 6.

A variation of this embodiment is shown in FIG. 38. Parts common to FIG. 37 and to FIG. 38 are given the same reference numerals and are not described in detail.

In the embodiment of FIG. 38, the fragrance source is identical to the fragrance source of FIGS. 5 and 6 with both windows 41 a,41 b being within the outlet 100. The two fragrances in the fragrance source are chosen to combine at the point of dispersion to give a desired single fragrance. This arrangement is particularly useful where the desired fragrance is formed of components that degrade if kept together. By combining them only at the point of dispersion, this degradation is avoided.

Of course, the fragrance source of FIGS. 8 and 9 could also be used with either of these embodiments. Also, the size of the window 41 a, 41 b may be controlled by an arrangement similar to that described above with reference to FIGS. 16 and 17.

Where two fragrances are to be evaporated alternately, the evaporation need not be by a forced air flow. Referring next to FIG. 39, a fifth form of fragrance disperser includes two sources of fragrance 103 a,103 b. Each source 103 a,103 b includes a container 104 a,104 b and an associated wick 105 a,105 b projecting from the associated container 104 a,104 b. Each wick 105 a,105 b is surrounded by an associated heater 106 a,106 b. Each heater 106 a,106 b is connected to a control board 107 which in turn is connected to an external power supply (not shown). The control board passes current to the heaters 106 a,106 b in accordance with a predetermined programme. As each heater receives current, its temperature rises and this in turn evaporates fragrance from the associated wick 105 a,105 b. The control board may be arranged to provide a cycle of evaporation similar to that shown in FIG. 7. In addition, controls may be provided for different timing protocols as described above with reference to FIG. 15. Also, varying the power supply varies the temperature of the heater and thus the volume of fragrance evaporated.

An alternative arrangement is shown in FIG. 40. Parts common to FIGS. 39 and 40 are given the same reference numerals and are not described in detail. In this embodiment, the heaters 106 a,106 b are omitted and the wicks 108 a,108 b are formed of or include an electrically conductive material which is connected to the control board 107. Accordingly, when electrical current is supplied to either wick 108 a,108 b, the temperature of the wick is raised to evaporate fragrance.

Any of the fragrance dispersers described above with reference to FIGS. 1 to 4 or 10 to 19 or 27 to 31 may be mounted on a wall. Referring next to FIG. 41, parts common to those Figures and to FIG. 41 will not be described in detail and will be given the same reference numerals. Referring to FIG. 41, the cover 15 is continuous with the air inlet 26 omitted. Instead, an air inlet 114 is provided on the back wall 13. In addition, an electrical connector 115 projects from the back wall 13 and includes pins, one of which is shown at 116 received in an electrical socket on a vertical surface 117 such as a wall to support the fragrance disperser and provide electrical power. The location of the air inlet 114 is a safety feature since it prevents, for example, fingers being inserted into the path of the fan 11. 

1. A fragrance disperser (10) comprising a source of fragrance (12; 46), charactised by means (11; 101; 106 a, 106 b; 108 a, 108 b) for generating a flow of air to release said fragrance:
 2. A disperser according to claim 1 characterised in that two sources of fragrance (37 a, 37 b; 55 a, 55 b; 58 a, 58 b; 81 a, 81 b; 88 a, 88 b; 103 a, 103 b are provided, said means (11; 101; 106 a, 106 b; 108 a, 108 b) being selectively operable to release either fragrance.
 3. A disperser according to claim 1 or claim 2, characterised in that said means comprises a fan (11; 101).
 4. A disperser according to claim 3 when dependent on claim 2, characterised in that each fragrance source (37 a, 37 b; 55 a, 55 b; 58 a, 58 b; 81 a, 81 b; 88 a, 88 b) has an associated air flow path (29 a, 29 b; 60 a, 60 b; 83 a, 83 b), the fan (11) being operable to generate a flow of air along the flow path (29 a, 29 b; 60 a, 60 b; 83 a, 83 b) of the selected fragrance.
 5. A disperser according to claim 4 characterised in that a closure (70) is provided for closing the flow path (29 a, 29 b; 60 a, 60 b; 83 a, 83 b) of the non-selected fragrance.
 6. A disperser according to claim 2, claim 3 when dependent on claim 2 or claim 4 or claim 5 characterised in that said fan (11) is driven by a motor (21), the direction of rotation of the fan (11) being reversible to provide respective different air flows, each air flow releasing a respective fragrance.
 7. A disperser according to claim 6 when dependent on claim 3 characterised in that one direction of rotation of the fan (11) produces a fragrance releasing air flow in a first path (29 a; 60 a; 83 a) and the other direction of rotation of the fan produces a fragrance releasing air flow in a second flow path (29 b; 60 b; 83 b).
 8. A disperser according to claim 7 characterised in that the fan (11) comprises a plurality of blades rotatable about an axis (22), the fan (11) being surrounded by a housing having an axis co-axial with the fan axis (22) and having two outlets, each outlet leading to a respective flow path (29 a, 29 b; 60 a, 60 b; 83 a, 83 b).
 9. A disperser according to claim 8 characterised in that each outlet extends in a generally tangential direction relative to said axis (22).
 10. A disperser according to claim 8 or claim 9 characterised in that the housing is shaped to provide a space between the radially outermost end of the fan (11) and the housing that increases in volume towards the associated outlet.
 11. A disperser according to any one of claims 8 to 10 characterised in that each blade lies in a plane including said axis (22) and a radius relative to said axis, the blades being equiangularly arranged about said axis (22).
 12. A disperser according to claim 6 and claim 7 when dependent on claim 5 characterised in that said closure (70) comprises a shutter (69), rotation of the fan (11) in said one direction causing the shutter (69) to close said second air path (29 b; 60 b; 83 b) and rotation of the fan (11) in said other direction causing the shutter to close said first air path (29 a; 60 a; 83 a).
 13. A disperser according to claim 12 characterised in that the shutter (69) is arcuate, is movable in an angular direction and is connected to the motor (21) by a frictional connection (74, 75; 77, 79) such that rotation of the motor (21) in one sense produces a frictional force that moves the shutter (69) in one sense and rotation of the motor (21) in an opposite sense moves the shutter (69) in an opposite sense.
 14. A disperser according to claim 12 characterised in that a clutch mechanism (77, 78, 79) is provided between said motor (21) and said shutter (69) so that rotation of the motor (21) being transmitted to said fan (11) via said clutch (77, 78, 79) to close an air path, the clutch then disengaging the motor (21) from the fan (11).
 15. A disperser according to claim 2 or any claim appendant thereto characterised in that control means (23; 107; 111; 112; 113; 210 a, 210 b; 220 a, 220 b) are provided for controlling the release of said fragrances.
 16. A disperser according to claim 15 characterised in that the control means (23; 107; 111; 112; 113) cause release of the fragrances alternately.
 17. A disperser according to claim 16 characterised in that the control means (23; 107; 111; 112; 113) causes release of the fragrances continuously.
 18. A disperser according to claim 16 characterised in that the control means (23; 107; 111; 112; 113) causes release of the fragrances with a time interval (T2, T4) between successive releases (T1, T3).
 19. A disperser according to any one of claims 16 to 18 characterised in that the times of release (T1, T3) of the two fragrances are equal.
 20. A disperser according to any one of claims 16 to 18 characterised in that the times of release (T1, T3) of the two fragrances are unequal.
 21. A disperser according to any one of claims 16 to 20 characterised in that the control means (23; 107; 111; 112; 113; 210 a, 210 b; 220 a, 220 b) are operable to alter the rate of release of the fragrances.
 22. A disperser according to claim 21 when dependent on claim 18 characterised in that the rate is controlled by altering the times of release (T1, T3).
 23. A disperser according to claim 21 when dependent on claim 18 or on claim 22 characterised in that the rate is controlled by altering the time intervals (T2, T4).
 24. A disperser according to claim 23 characterised in that the rate is controlled by altering both the times of release (T1, T3) and the time intervals (T2, T4) such that the ratio of time of release to time interval (T1:T2; T3:T4) is unchanged.
 25. A disperser according to any one of claims 21 to 24 characterised in that the control means (23; 107; 112; 113; 210 a, 210 b; 220 a, 220 b) are operable to increase the rate of release of the fragrances relative to a datum rate of release.
 26. A disperser according to any one of claims 21 to 24 characterised in that the control means (23; 107; 111; 210 a, 210 b; 220 a, 220 b) are operable to decrease the rate of release of the fragrances relative to a datum rate of release.
 27. A disperser according to any one of claims 21 to 26 characterised by including manually operable means (111, 112, 113; 212 a, 212 b; 228 a, 228 b) for operating the control means (23; 107; 210 a, 210 b; 220 a, 220 b) to alter the rate of release of the fragrances.
 28. A disperser according to claim 27 characterised in that the disperser includes a fragrance flow path outlet (41 a, 41 b; 68 a, 68 b) and in that the control means (210 a, 210 b) comprises a manually adjustable shutter for varying the size of said outlet.
 29. A disperser according to any one of claims 15 to 28 characterised in that at least one source of fragrance (37 a, 37 b; 55 a, 55 b; 58 a, 58 b; 81 a, 81 b; 88 a, 88 b; 103 a, 103 b) is provided with means for controlling the control means (23; 107) to alter the release of said fragrances.
 30. A disperser according to claim 29 characterised in that at least one source of fragrance (58 a) includes a pin (109) engageable with a switch (110) included in the control system (23;107), engagement of the pin (109) with the switch (110) controlling said control means (23;107) to alter the release of said fragrances.
 31. A disperser according to any one of claims 1 to 30 in combination with at least one container (82 a, 82 b; 88 a, 88 b) according to any one of claims 37 to
 39. 32. A disperser according to claim 31 when dependent on claim 4 characterised in that two containers (82 a, 82 b; 88 a, 88 b) are provided, each flow path being formed at least partially by an outlet (83 a, 83 b; 90) of an associated container.
 33. A disperser according to claim 31 or claim 32 characterised in that the or each container (82 a, 82 b; 88 a, 88 b) is separable from the disperser for replacement by another container (82 a, 82 b; 88 a, 88 b).
 34. A disperser according to claim 2 and any claim appendant thereto characterised in that the two sources of fragrance are provided by a pair of containers (82 a, 82 b; 88 a, 88 b) according to any one of claims 38 to
 46. 35. A disperser according to claim 8 or any claim appendant to claim 8 characterised in that the housing includes an air inlet (114) and includes a mounting (115) for supporting the housing on a vertical surface (117), the air inlet (114) being provided on a side of the housing associated with said mounting (115).
 36. A disperser according to any one of claims 1 to 26 in combination with a fragrance source according to any one of claims 47 to
 52. 37. A fragrance container (82 a, 82 b) comprising a reservoir for receiving a liquid fragrance and an outlet (83 a, 83 b) to the reservoir, the outlet (83 a, 83 b) defining a path for a flow of air to release fragrance in the reservoir.
 38. A container according to claim 37 characterised in that said outlet (83 a, 83 b) includes a passage for said air flow having an entrance (84 a, 84 b) at an end of the outlet remote from the reservoir and an exit (85 a, 85b) for fragrance laden air adjacent said reservoir.
 39. A container according to claim 38 characterised in that a wick (87 a, 87 b) is located in said passage (83 a, 83 b) for wicling liquid fragrance from the reservoir to the passage.
 40. A pair of containers (88 a, 88 b) each comprising a reservoir (89) for receiving a liquid fragrance and an outlet to the reservoir (90), the containers (88 a, 88 b) being used with respective side surfaces (97 a, 97 b) closely adjacent or in contact, means (95, 96) being provided for indicating that the containers are intended to be used as a pair.
 41. A pair of containers according to claim 40 characterised in that the reservoirs (89) contain complementary fragrances.
 42. A pair of containers according to claim 40 or claim 41 characterised in that said side surfaces (97 a, 97 b) have complementary non-planar shapes so that the side surfaces inter-engage when the containers (88 a, 88 b) are side-by-side.
 43. A pair of containers according to claim 40 or claim 41 characterised in that the containers (88 a, 88 b) have respective surfaces leading to said side surfaces (97 a, 97 b), said leading surfaces carrying respective indicia (95, 96) that together form a single pattern.
 44. A pair of containers according to claim 43 characterised in that the indicia (95, 96) are raised or lowered portions of said leading surfaces.
 45. A pair of containers according to claim 43 characterised in that the indicia (95, 96) are two dimensional.
 46. A pair of containers according to any one of claims 40 to 45 and including respective outlets (83 a, 83 b) according to any one of claims 37 to
 39. 47. A fragrance source (12; 46) characterised in that it comprises a back sheet (31; 47) and a front sheet (40; 48) with a wicking material (37 a, 37 b) therebetween the back sheet (31; 47) and the front sheet (40; 48) being joined together along a closed line (42, 43, 44; 53, 54) to define a reservoir for fragrance, a portion of the wicking material (37 a, 37 b; 56 a, 56 b) being exposable outside the closed line (42, 43, 44; 53, 54) for releasing the fragrance, the join being such as to allow the wicking material (37 a, 37 b; 56 a, 56 b) to wick fragrance from the reservoir to the exposable portion.
 48. A source according to claim 47 characterised in that the exposable portion is covered by a removable cover (34).
 49. A source according to claim 48 characterised in that the cover (34) is formed by a portion of the back sheet (31) extending beyond the front sheet (40) and folded over the front sheet (31).
 50. A source according to any one of claims 47 to 49 characterised in that the closed line (42,43, 44) defines two reservoirs, each containing a respective fragrance, each reservoir being associated with a respective exposable release portion.
 51. A source according to any one of claims 47 to 50 characterised in that the back sheet (31; 47) and the front sheet (40; 48) are formed from plastics materials, the join (42, 43, 44; 53, 54) being by a weld between the sheets (31, 40; 47, 48).
 52. A source according to any one of claims 47 to 51 characterised in that the front sheet (3 1; 47) and the back sheet (40; 48) are formed in one piece.
 53. A source according to any one of claims 47 to 52 characterised by further comprising a source of electric power (45) connected to the back sheet (31; 47).
 54. A source according to any one of claims 47 to 53 in combination with a heating means for selectively heating the exposable portion to evaporate fragrance from said portion.
 55. A source according to claim 54 characterised in that the wicking material (37 a, 37 b; 56 a, 56 b) is electrically conductive to provide said heating means.
 56. A source according to claim 54 when dependent on claim 53 characterised in that the electrically conductive material is powered by the source of electric power (45).
 57. A source according to claim 55 characterised in that the electrically conductive material is powered by mains electricity.
 58. A source according to any one of claims 54 to 57 when dependent on claim 50 characterised in that each exposable portion is associated with a respective heater, the heaters being selectively operable to evaporate the associated fragrance.
 59. A fragrance disperser (10) comprising two sources of fragrance (37 a, 37 b; 55 a, 55 b; 58 a, 58 b; 81 a, 81 b; 88 a, 88 b; 103 a, 103 b), means (11; 101; 106 a, 106 b; 108 a, 108 b) for dispersing fragrance from said sources and a control system (23; 107; 111, 112,113; 210 a, 210 b; 220 a, 220 b) for controlling said dispersing means (11; 101; 106 a, 106 b; 108 a, 108 b).
 60. A fragrance disperser according to claim 59 characterised in that each source of fragrance includes a container for fragrance and a wick (37 a, 37 b; 56 a, 56 b; 59 a, 59 b; 87 a, 87 b; 93, 105 a, 105 b; 108 a, 108 b), said dispersing means releasing fragrance from said wick.
 61. A disperser according to claim 59 or claim 60 characterised in that each fragrance has an associated flow path (29 a, 29 b; 60 a, 60 b; 83 a, 83 b) and in that said control system (210 a, 210 b;) comprises means for controlling the size of an outlet (41 a, 41 b; 68 a, 68 b) of each respective flow path (29 a, 29 b; 60 a, 60 b; 83 a, 83 b) to control the volume of fragrance emitted.
 62. A disperser according to claim 61 characterised in that said means comprises a slidable shutter (211 a, 211 b).
 63. A disperser according to claim 60 characterised in that said control system (220 a, 220 b) comprises means for controlling the exposed surface area of each respective wick (37 a, 37 b; 56 a, 56 b; 59 a, 59 b; 87 a, 87 b; 93; 105 a, 105 b; 108 a, 108 b).
 64. A disperser according to claim 63 characterised in that said means comprises a cover (222 a, 222 b) slidably mounted on said wick.
 65. A disperser according to any one of claims 61 to 64 characterised in that said control means is manually operable.
 66. A disperser according to claim 59 or claim 60 characterised in that the dispersing means include a fan (11) for generating a flow of air which evaporates the fragrances and disperses the fragrances.
 67. A disperser according to claim 66 characterised in that the control system (23; 111, 112, 113) is operable to control the power supplied to the fan, thereby controlling the speed of the fan.
 68. A disperser according to claim 59 or claim 60 characterised in that the dispersing means include electrical heating means (106 a, 106 b; 108 a, 108 b) which evaporates the fragrances for dispersion.
 69. A disperser according to claim 68 characterised in that the control system (107; 111,112,113) is operable to control the power supplied to the heater, thereby controlling the heater temperature.
 70. A disperser according to claim 68 or claim 69 characterised in that the heating means includes two heaters (106 a, 106 b; 108 a, 108 b), each heater being associated with a respective fragrance source (103 a, 103 b).
 71. A disperser according to claim 70 when dependent on claim 59 characterised in that each heater (106 a, 106 b) surrounds an associated wick (105 a, 105b).
 72. A disperser according to claim 68 or claim 69 when dependent on claim 60 characterised in that each wick (108 a, 108 b) is electrically conductive to form said electrical heating means (108 a, 108 b).
 73. A disperser according to claim 72 characterised in that each wick (108 a, 108 b) is formed from a woven material, said woven material including electrically conductive threads forming said electrical heating means.
 74. A disperser according to any one of claims 59 to 73 characterised in that said control system (23; 107; 111, 112, 113) causes release of the fragrances with a time interval (T2, T4) between successive releases (T1, T3).
 75. A disperser according to claim 74 characterised in that the control system (23; 107; 111, 112, 113) is operable to alter the rate of release of the fragrances by altering the times of release (T1, T3).
 76. A disperser according to claim 74 or claim 75 characterised in that the control system (23; 107; 111, 112, 113) is operable to alter the rate of release of the fragrances by altering the time intervals (T2, T4).
 77. A disperser according to claim 76 when dependent on claim 75 characterised in that the rate is controlled by altering both the times of release (T1, T3) and the time intervals (T2, T4) such that the ratio of time of release to time interval (T1: T2; T3: T4) is unchanged. 